RAIDpictures - 9/7/2010 RAID - Wikipedia, the free...

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RAID 0 increases with more disks in the array (at a minimum, catastrophic data loss is twice as likely compared to single drives without RAID). A single disk failure destroys the entire array because when data is written to a RAID 0 volume, the data is broken into fragments called blocks. The number of blocks is dictated by the stripe size , which is a configuration parameter of the array. The blocks are written to their respective disks simultaneously on the same sector. This allows smaller sections of the entire chunk of data to be read off the drive in parallel, increasing bandwidth. RAID 0 does not implement error checking, so any error is uncorrectable. More disks in the array means higher bandwidth, but greater risk of data loss. 2 1 0 (none) RAID 1 Mirroring without parity or striping. Data is written identically to multiple disks (a "mirrored set"). Although many implementations create sets of 2 disks, sets may contain 3 or more disks. Array provides fault tolerance from disk errors or failures and continues to operate as long as at least one drive in the mirrored set is functioning. Increased read performance occurs when using a multi-threaded operating system that supports split seeks, as well as a very small performance reduction when writing. Using RAID 1 with a separate controller for each disk is sometimes called duplexing . 2 1/n n-1 disks Bit-level striping with dedicated 1 disk when the 9/7/2010 RAID - Wikipedia, the free encyclopedia
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RAID 2 Hamming-code parity. All disk spindle rotation is synchronized, and data is striped such that each sequential bit is on a different disk. Hamming-code parity is calculated across corresponding bits on disks and stored on one or more parity disks. Extremely high data transfer rates are possible. 3 1 - 1/n · log 2 (n-1) fact that the disk is corrupt isn't found by any thing but the hamming -recover- record- code. RAID 3 Byte-level striping with dedicated parity. All disk spindle rotation is synchronized, and data is striped such that each sequential byte is on a different disk. Parity is calculated across corresponding bytes on disks and stored on a dedicated parity disk. Very high data transfer rates are possible. 3 1 - 1/n 1 disk RAID 4 Block-level striping with dedicated parity. Identical to RAID 5, but confines all parity data to a single disk, which can create a performance bottleneck. In this setup, files can be distributed between multiple disks. Each disk operates independently which allows I/O requests to be performed in parallel, though data transfer speeds can suffer due to the type of parity. The error detection is achieved through dedicated parity and is stored in a separate, single
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RAIDpictures - 9/7/2010 RAID - Wikipedia, the free...

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